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GLOSSARY

NAP - NETWORK ACCESS POINT
NARROWBAND
NAT - NETWORK ADDRESS TRANSLATION
NetBEUI - NetBIOS EXTENDED USER INTERFACE
NetBIOS - NETWORK BASIC INPUT/OUTPUT SYSTEM
NETMASK
NETSCAPE
NETWORK
NAS - NETWORK ACCESS SERVER
NETWORK ENCRYPTION
NIC - NETWORK INTERFACE CARD
NETWORK LAYER
NOS - NETWORK OPERATING SYSTEM
NOC - NETWORK OPERATION CENTER
NSP - NETWORK SERVICE PROVIDER
NETWORKING
NODE
nslookup

NAP, Network Access Point is one of several major Internet interconnection points that serve to tie all the Internet access providers together so that, for example, an AT&T user in Portland, Oregon can reach the Web site of a Bell South customer in Miami, Florida. Originally, four NAPs - in New York, Washington, D.C., Chicago, and San Francisco - were created and supported by the National Science Foundation as part of the transition from the original U.S. government-financed Internet to a commercially operated Internet. Since that time, several new NAPs have arrived, including WorldCom's "MAE West" site in San Jose, California and ICS Network Systems' "Big East."

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NARROWBAND describes telecommunication that carries voice information in a narrow band of frequencies. More specifically, the term has been used to describe a specific frequency range set aside by the U.S. Fcc for mobile or radio services, including paging systems, from 50 cps to 64 Kbps.

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NAT Network Address Translation, is the translation of an Internet Protocol address (IP address) used within one network to a different IP address known within another network. One network is designated the inside network and the other is the outside. Typically, a company maps its local inside network addresses to one or more global outside IP addresses and unmaps the global IP addresses on incoming packets back into local IP addresses. This helps ensure security since each outgoing or incoming request must go through a translation process that also offers the opportunity to qualify or authenticate the request or match it to a previous request. NAT also conserves on the number of global IP addresses that a company needs and it lets the company use a single IP address in its communication with the world.
NAT is included as part of a router and is often part of a corporate firewall. Network administrators create a NAT table that does the global-to-local and local-to-global IP address mapping. NAT can also be used in conjunction with policy routing. NAT can be statically defined or it can be set up to dynamically translate from and to a pool of IP addresses. Cisco's version of NAT lets an administrator create tables that map:

NAT is described in general terms in RFC 1631. which discusses NAT's relationship to Classless Interdomain Routing (CIDR) as a way to reduce the IP address depletion problem. NAT reduces the need for a large amount of publicly known IP addresses by creating a separation between publicly known and privately known IP addresses. CIDR aggregates publicly known IP addresses into blocks so that fewer IP addresses are wasted. In the end, both extend the use of IPv4 IP addresses for a few more years before IPv6 is generally supported.

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NetBEUI, NetBIOS Extended User Interface, is a new extended version of NetBIOS, the program that lets computers communicate within a local area network. NetBEUI (pronounced net-BOO-ee) formalizes the frame format (or arrangement of information in a data transmission) that was not specified as part of NetBIOS. NetBEUI was developed by IBM for its LAN Manager product and has been adopted by Microsoft for its Windows NT, LAN Manager, and Windows for Workgroups products. Hewlett-Packard and DEC use it in comparable products.
NetBEUI is the best performance choice for communication within a single LAN. Because, like NetBIOS, it does not support the routing of messages to other networks, its interface must be adapted to other protocols such as Internetwork Packet Exchange or TCP/IP. A recommended method is to install both NetBEUI and TCP/IP in each computer and set the server up to use NetBEUI for communication within the LAN and TCP/IP for communication beyond the LAN.

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NetBIOS, Network Basic Input/Output System, is a program that allows applications on different computers to communicate within a local area network (LAN). It was created by IBM for its early PC Network, was adopted by Microsoft, and has since become a de facto industry standard. NetBIOS is used in Ethernet, token ring, and Windows NT networks. It does not in itself support a routing mechanism so applications communicating on a wide area network (WAN) must use another "transport mechanism" (such as Transmission Control Protocol) rather than or in addition to NetBIOS.
NetBIOS frees the application from having to understand the details of the network, including error recovery (in session mode). A NetBIOS request is provided in the form of a Network Control Block (NCB) which, among other things, specifies a message location and the name of a destination.

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NETMASK is a string of 0's and 1's that mask or screen out the network part of an IP address (IP) so that only the host computer part of the address remains. The binary 1's at the beginning of the mask turn the network ID part of the IP address into 0's. The binary 0's that follow allow the host ID to remain. A frequently-used netmask is 255.255.255.0. (255 is the decimal equivalent of a binary string of eight ones.) Used for a Class C subnet (one with up to 255 host computers), the ".0" in the "255.255.255.0" netmask allows the specific host computer address to be visible.

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NETSCAPE is one of the two most popular Web browser and also the name of a company, Netscape Communications, now owned by America Online (AOL). Currently, almost all Internet users use either Netscape's browser or Microsoft's Internet Explorer (MSIE) browser, and many users use both. Although Netscape was initially the predominant product in terms of usability and number of users, Microsoft's browser is now considered superior by many users (although many other users see them as roughly equivalent) and has taken a slight lead in usage.
Netscape's browser originally was called "Navigator," and is still called that in the suite of software, Communicator, of which it is now a part. Navigator was developed in 1995 by a team led by Marc Andreessen, who created Mosaic, the first Web browser that had a graphical user interface, at the University of Illinois' National Center for Supercomputing Applications (NCSA) in 1993.

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NETWORK, a series of points or node interconnected by communication paths. Networks can interconnect with other networks and contain subnetworks.

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NAS Network Access Server, is a computer server that enables an independent service provider (ISP) to provide connected customers with Internet access . A network access server has interfaces to both the local telecommunication service provider such as the phone company and to the Internet backbone.

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NETWORK ENCRYPTION (sometimes called network layer, or network level encryption) is a network security process that applies crypto services at the network transfer layer - above the data link level, but below the application level. The network transfer layers are layers 3 and 4 of the Open Systems Interconnection (OSI) reference model, the layers responsible for connectivity and routing between two end points. Using the existing network services and application software, network encryption is invisible to the end user and operates independently of any other encryption processes used. Data is encrypted only while in transit, existing as plaintext on the originating and receiving hosts.
Network encryption is implemented through Internet Protocol Security (IPsec), a set of open Internet Engineering Task Force (IETF)standards that, used in conjunction, create a framework for private communication over IP networks. IPSec works through the network architecture, which means that end users and applications don't need to be altered in any way. Encrypted packets appear to be identical to unencrypted packets and are easily routed through any IP network.

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NIC Network Interface Card, is a computer circuit board or card that is installed in a computer so that it can be connected to a network. Personal computers and workstations on a local area network (LAN) typically contain a network interface card specifically designed for the LAN transmission technology, such as Ethernet or token ring. Network interface cards provide a dedicated, full-time connection to a network. Most home and portable computers connect to the Internet through as-needed dial-up connection. The modem provides the connection interface to the Internet service provider.

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NETWORK LAYER In the Open Systems Interconnection (OSI) communications model, the Network layer knows the address of the neighboring nodes in the network, packages output with the correct network address information, selects routes and Quality of Service, and recognizes and forwards to the Transport layer incoming messages for local host domains. Among existing protocol that generally map to the OSI network layer are the Internet Protocol (IP) part of TCP/IP and NetWare IPX/SPX. Both IP Version 4 and IP Version 6 (IPv6) map to the OSI network layer.

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NOS Network Operating System, is a computer operating system system that is designed primarily to support workstation , personal computer , and, in some instances, older terminal that are connected on a local area network (LAN. Artisoft's LANtastic, Banyan VINES, Novell's NetWare, and Microsoft's LAN Manager are examples of network operating systems. In addition, some multi-purpose operating systems, such as Windows NT and Digital's OpenVMS come with capabilities that enable them to be described as a network operating system.
A network operating system provides printer sharing, common file system and database sharing, application sharing, and the ability to manage a network name directory, security, and other housekeeping aspects of a network.

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NOC Network Operations Center, is a place from which a telecommunications network is supervised, monitored, and maintained. An enterprise with large networks as well as large network service providers such as GTE Internetworking typically have a network operations center, a room containing visualizations of the network or networks that are being monitored, workstations at which the detailed status of the network can be seen, and the necessary software to manage the networks. The network operations center is the focal point for network troubleshooting, software distribution and updating, router and domain name management, performance monitoring, and coordination with affiliated networks.

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NSP Network Service Provider, is a company that provides backbone services to an Internet service provider (ISP), the company that most Web users use for access to the Internet. Typically, an ISP connects at a point called an Internet Exchange (IX) to a regional ISP that in turn connects to an NSP backbone. In the U.S., major NSPs include MCI, Sprint, UUNET, AGIS, and BBN.

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NETWORKING is the construction, design, and use of network, including the physical (cabling, hub, bridge, switch, router, and so forth), the selection and use of telecommunication protocol and computer software for using and managing the network, and the establishment of operation policies and procedures related to the network.

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NODE is a connection point, either a redistribution point or an end point for data transmissions. In general, a node has programmed or engineered capability to recognize and process or forward transmissions to other nodes.

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nslookup is the name of a program that lets an Internet server administrator or user enter a host name (for example, "whatis.com") and find out the corresponding IP address. It will also do reverse name lookup and find the host name for an IP address you specify.
For example, if you entered "cnsny.net", you would receive as a response our IP address, which happens to be :
65.215.31.31
Or if you entered "65.215.31.31", it would return "cnsny.net".
nslookup sends a domain name query packet to a designated (or defaulted) domain name system (DNS) server. Depending on the system you are using, the default may be the local DNS name server at your service provider, some intermediate name server, or the root server system for the entire domain name system hierarchy.
Using the Linux and possibly other versions of nslookup, you can locate other information associated with the host name or IP address, such as associated mail services. nslookup is often included with a UNIX-based operating system. Free versions exist that can be added to Windows operating systems. A more limited alternative to nslookup for looking up an IP address is the ping command.

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